It is proposed to restrict the work for the second year of the grant (5/1/1975 - 4/30/1976) to the detailed examination of a new pathway of mevalonate metabolism not leading to sterols, called the "trans-methylglutaconate shunt" and discovered in the P.I.'s laboratory, as it is believed that impairments of this metabolic pathway may be responsible for the secondary (non-genetic) hypercholesterolemias in man.